RSSManagement potato storage
Identify the major storage disease problem prior to making any changes to storage management procedures.
Be aware that changes in potato storage management can impact other potato quality attributes, such as fry color and tuber sugar concentrations.
There are three basic tools of storage management:
temperature, humidity, and airflow.
Balanced use of these tools is the key to managing potato diseases in storage.
Cooling period
If potatoes are harvested with pulp temperatures above 60°F, cool them to at least 60°F within the first 2 to 3 days after harvest and maximize the duration of fresh-air intake. This is especially important for tubers with late blight, pink rot, Pythium leak, and soft rot because warmer temperatures promote faster decay.
Supply a high volume of air to the potatoes to decrease tuber temperature and to help dry out rotted or wet potatoes. Set-point temperatures may need to be decreased in a stair-step manner to optimize the duration of fresh air intake per day.
Start operating the ventilation system as soon as the first two to three ducts are covered during loading. Continue to decrease storage temperatures to the desired curing temperature.
Some special circumstances such as colder-than-recommended pulp temperatures or excessive disease may require the advice of an expert. For instance, rapidly warming cool potatoes may cause condensation to form on the surface of the potato and elevate the potential for disease progression.
Curing period
Proper management of the storage facility during the wound healing or “curing period” is critical. The curing period is important for proper healing of cuts and bruises, reducing pathogen spread, and keeping shrinkage losses at a minimum. Wound healing requires oxygen, high humidity, and favorable temperatures.
The recommended storage regime for wound healing and curing is typically 50 to 55°F for 2 to 3 weeks with good ventilation and a relative humidity of 95% and above. Even these relatively cool temperatures will promote rapid breakdown when storage diseases such as pink rot and Pythium leak are present.
Therefore temperatures during curing may need to be lowered to 50°F if disease incidence and severity are high (more than 5% wet rot). However, curing temperatures below
50°F may delay wound healing and are generally not recommended.
Use continuous ventilation to dry out wet potatoes. If “hot spots” begin to develop during curing, supply high airflow to the area to help prevent additional pathogen spread.
Airflow must be sufficient to remove water given off by the decaying tubers. Supplemental ventilation can be supplied by auxiliary fans on top of the pile or in the ducts below troublespots.
Holding period.
After the required curing period, reduce the storage temperature from the curing to the holding temperature as quickly as possible but generally no faster than 0.5°F per day. Limiting the amount of time diseased tubers are held at warmer temperatures will decrease the rate of disease progression.
A slower ramping rate may be more appropriate for potatoes to be processed where sugar concentrations and fry color are a concern.
Although lower holding temperatures typically decrease the rate of disease progression, any storage decision involving temperature adjustments must take into consideration the end-use of the potato. Processing potatoes typically need to be stored at higher temperatures (44° to 55°F) than seed and fresh market potatoes (37° to 45°F) and therefore the luxury of low storage temperatures is not available.
Continuous fan operation and high airflow may still be necessary to dry out wet or problem potatoes, especially those with soft rot, pink rot, or Pythium leak. Continuous ventilation will also reduce the chance for condensation to occur in the storage facility.
Keep in mind that low holding temperatures, while an effective management tool for many situations, are no guarantee that disease progression will stop.
Depending upon the nature and percentage of rot in the storage, the pile may need additional drying ventilation with reduced-humidity air. However, reduced humidity results in additional shrinkage and also delays wound healing, which can increase the incidence of dry rot.
Decreasing relative humidity in storage to 85% or less can also decrease the secondary spread of the silver scurf pathogen. Still, evaluate other management strategies before reducing relative humidity.
Potato Vegetable Keep Sack by Orka
* Double draw-string designed hanging sack protects vegetables from light and delays the sprouting process
* All-cotton design perfectly sized for potatoes; holds up to 8 pounds
* Draw-string at both ends to add and remove vegetables
* Convenient hanging loop so vegetables remain handy and within reach
* Machine washable; measures 1/2 by 8-1/2 by 14-1/8 inches
